Why 2013 May Be Another 1973 for Stocks

"October. This is one of the peculiarly dangerous months to speculate in stocks. The others are July, January, September, April, November, May, March, June, December, August, and February."

Mark Twain may not have thought much of the market, much less trying to time it, but then he was a notoriously awful investor. Some good ones—notably Jeremy Grantham of Grantham Mayo Van Otterloo—have prospered by heeding the patterns...